Tool gripping and guiding device for tool exchanger for punching and nibbling machines

ABSTRACT

An apparatus for transferring a tool from a non-working position to a working position in punching machines or the like, wherein the means for transferring the tool comprises a fluid actuated member with tool gripping means disposed on the end thereof.

United States Patent 1191 11] 3,765,291 Stenfeldt [451 ()Ct. 16, 1973TOOL GRIPPING AND GUIDING DEVICE [56] References Cited FOR TOOLEXCHANGER FOR PUNCHING UNITED STATES ENT AND NIBBLING MACHINES 3,431,6353/1969 Balding 29/568 [76] Inventor: Jan-Olof Stenteldt, Meteorgatan 6,5 313435293 10/1967 Sfidgwick 29/568 v Gothenburg, Sweden 3,590,4705/1969 Brainhard 29/568 3,277,568 10/1966 Wetzel 29/568 [22} Filed: July23, 1971 [211 App] NW 165,086 Primary Examiner-Andrew R. JuhaszAssistant Examiner-W. D. Bray Att0mey-R0bert E. Burns et al. [30]Foreign Application Priority Data Aug. 20, 1970 Sweden 11352 70 [57]ABSTRACT An apparatus for transferring a tool from a non- [52] US. Cl.83/563, 29/568, 2144;283, working position to a working position inpunching [51] Int Cl B26d 5/08 machines or the like, wherein the meansfor transfer- Field I563 564 ring the tool comprises a fluid actuatedmember with 83/701; 214/1 BC, 1 BD, 1 BH, 1 BV tool gripping meansdisposed on the end thereof.

6 Claims, 6 Drawing Figures Pmmmm Is 1913 3. 765291 SHEET 1 OF 4 TOOLGRIPPING AND GUIDING DEVICE FOR TOOL EXCHANGER FOR PUNCll-IING ANDNIBBLING MACHINES The present invention is relating to machines forpunching, nibbling and similar operations, wherein sheet material isworked between two tools movable relative to each other, said toolsbeing positioned one above the other and comprising an upper movabletool and a lower fixed tool. It is important that the tools areaccurately aligned for correct position of cooperating working surfaces,for example when said surfaces define a cutting clearance there between.In conventional machines of this kind the mounting of the tools iscommonly carried out in the form of a manual operation and the alignmentof the tools can be made without difficulty by means of conventionalmethods in connection with the mounting.

In combined operations when using different tools it is desirable toprovide said machines with means for automatic tool exchange, whereby aquick exchange of tools according to a predetermined program isobtained. The US. Pat. specification No. 2,7 01,0l7 gives an example ofa machine having such equipment. Said specification discloses arevolving punching machine having a C-shaped frame and carrying itstools at the extremities of the arms of the frame. The tools comprise alower fixed die and a punch movable in a vertical direction against saiddie. Within the throat of the frame are received two revolving discs ortool revolvers positioned one above the other and aligned on a commonaxis, said revolving units carrying cooperating pairs of tools along theperiphery thereof. By means of an indexing mechanism and by rotation ofthe revolvers the respective pairs of tools can be brought intooperational position in the machine. In operational position the lowertool is secured in fixed position on its revolver, whereas the uppertool is axially movable in its revolver against the lower tool. Amechanism engages the upper tool for performing the desired operation inthe machine. The tools are locked in operational position by lockingpistons engaging the periphery of the tool revolvers. The relativeposition of the tools is therefore entirely depending on the accuracy ofthe locking mechanism. The number of tools at disposition is furtherlimited to the very number of tools which can be received in the toolmagazine comprising an upper and a lower tool revolver only.

A development of this device in order to enable the reception of anincreased number of tools comprises a turret type magazine separatelymounted beside the machine, in which the respective cooperating pairs oftools are supported in positions relative to each other corresponding totheir operational position on a plurality of turret discs arranged inpairs on top of each other, whereby two parallel and simultaneouslyoperating tool exchange units are arranged for transport of therespective tools from the magazine to the operating position of the tooland for return transport in reversed direction. In this apparatus therespective tool is seized by gripping means mounted on the tool exchangeunit, said gripping means being arranged for guiding the tools in theiroperational positions and in their turn being guided relative to themachine frame by means of locking pistons engaging the gripping meansadjacent the operational position of the too]. Also in this case theposition of the tool is depending on the accuracy of the lockingmechanism and the guiding stability of the gripping means.

The invention has for its object to provide a gripping and a guidingdevice for punching machines, nibbling machines and similar machineshaving a tool exchanger cooperating with a tool magazine of largecapacity for obtaining an accurate relative adjustment of the tools, andis characterized therein that each respective tool is fixedly secured orguided in operational position by means of a guiding element fixedlysecured on the machine and a cooperating combined gripping and guidingelement supported on the tool exchange unit, said elements receiving thetool there between in operational position.

In this device two cooperating tools are simultaneously transferred fromthe magazine to their operational positions, whereby one tool may belocked in a fixed position and the other tool may be guided for axialmotion against said first mentioned tool, as desired.

The tool exchange units are further arranged for cooperation with a toolmagazine mounted beside the machine and comprising a plurality of turretdiscs arranged in pairs on top of each other, thus enabling a greatnumber of tools to be received in the magazine.

A preferred embodiment of the invention is descirbed hereinbelow andwith reference to the accompanying drawings FIG. I is a plan view of thedevice according to the invention mounted on a punching machine or asimilar machine, portions of the outline of the machine and a turrettype magazine mounted beside the machine being indicated withdash-dotted lines.

FIG. 2 is a vertical cross section through line lIll in FIG. 3 showingthe guiding and gripping element for the lower tool in operationalposition.

FIG. 3 is a corresponding plan view of said units.

FIG. 4 is a partial section through line IVIV in FIG. 5 showing thegripping and guiding element for the upper tool in operational positionwith a tool inserted there between and with locking and releasingelements for the tool indicated.

FIG. 5 is a vertical section through line V-V in FIG. 4.

FIG. 6 is a diagrammatic exploded view of the tool exchanger withattached tool magazine.

Referring to FIG. 1 the device according to the invention comprises aunit mounted beside the machine frame for horizontal rotation about afulcrum 3 and including two slide systems l and 2 for movement inopposite directions. The unit is rotated about the axis of fulcrum 3 bymeans of a driving unit 8, preferably in the form of a pressure fluidoperated cylinder jack coupled to a rack and gear mechanism. Each slidesystem has a slide unit 4 and 5 respectively, for substantially radialmotion away from fulcrum 3 as driven by one of cylinder jacks 6 or 7.

Each slide unit 4, 5 is in its outer end supporting a combined grippingand guiding element 9, arranged for seizing a tool in a startingposition A in the tool magazine and for transferring said tool to anoperational position B in the machine. As generally indicated in FIG. 1,the tools are supported in the magazine along the periphery of therespective turret discs. A plurality of such turret discs may bepositioned on top of each other for vertical displacement to a positionfacing gripping element 9, as further explained below. When the tool hasbeen seized it is transferred to operational position B in the machinefor fixedly securing or guiding, respectively, during the machineoperation.

In the embodiment as shown the device is constructed for similtaneoustransfer of an upper and lower tool between starting position A andoperational position B, in both directions. In this case two toolexchange units 1 and 2 are positioned one above the other on the upperand lower side of the horizontal throat of the machine frame,respectively. Both units are identical except for the gripping andguiding elements 9 which are designed for receiving the upper and lowertools, respectively. In the embodiment as shown the lower tool isarranged for a fixed operational position, whereas the upper tool isarranged for axial motion when engaged by the driving mechanism of themachine in its operational position. In starting position A therespective pairs of tools including an upper and lower tool aresupported at the periphery of turret disc pairs in the magazine, in aposition corresponding to the operational position of the tools.

FIG. 2 shows the combined gripping and guiding elements for the lowerfixed, or stationary, tool. These elements include the above mentionedelement 9 supported at the end of slide unit 4 or 5 and a cooperatingguiding element secured on the machine frame. These two elements formtogether in the embodiment shown a circular cylindrical internalsupporting surface 30 for engaging the correspondingly shaped externalperiphery of the lower tool. The tool is resting on an annularsupporting ring 31 secured to the machine frame. Element 9 has a lowerhalf-cylindrical recess therein corresponding to the external peripheryof ring 31 and is guided in operational position by said ring. Thecylindrical surface 30 of element 9 has a groove 25 therein forreceiving a correspondingly shaped key extending from the lower tool.Perpendicularly to the extension of said groove the element 9 has aboring receiving an axially displaceable slide 16. Said slide has alongitudinally extended portion 18 of swallow-tail cross section anddiverging towards the tool and so positioned that said portion 18extends into the groove 25 when slide 16 is displaced in axialdirection. The key extending from the tool (not shown) is received ingroove 25 and has a recess of swallow-tail section corresponding to thecross section of portion 18 for receiving said portion. Portion 18extends longitudinally of slide 16 over a distance adjacent the middlepart thereof and is axially defined by a recess 19 traversing the key 16and having a cross section of such dimension that the recess extendsbeyond groove 25 when recess 19 is aligned with groove 25. The slide 16can be axially displaced in its boring through element 9 for engagingportion 18 with the corresponding recess in the key extending from thetool into groove 25, or for positioning recess 19 in front of said toolkey. The axial displacement of slide 16 is limited by means of end stops22 and 23. Guiding pins 24 are axially slidable in corresponding boringsin element 9 for keeping the slide from rotation about its axis. Alocking device comprising a spring biassed ball engaging a recess inslide 16 prevents unintentional axial displacement of slide 16 in itsrespective end positions.

It is understood that the gripping and guiding element 9 by axialdisplacement of slide 16 can be set in a first position wherein a toolwith its guiding key can be attached to element 9, and in a secondposition wherein the tool is locked to element 9 by the portion 18 ofslide 16 engaging the swallow-tail recess in said key. For seizing atool in the magazine the element 9 is moved against the tool, theextending guiding key of which is accurately set in alignment withgroove 25, slide 16 being set in its first position. When element 9 isengaging the tool, slide 16 is displaced to its second position and thetool is locked to element 9. In this condition the tool is transferredto its operational position and is automatically aligned therein throughcooperating surfaces of ring 31 and element 9. In said position the toolis supported around its periphery by engagement against the cylindricalsupporting surface 30 and is axially locked through slide 16. In thisway the tool is held in an accurately fixed position in its stationaryoperational position.

Similar gripping and guiding elements for the upper tool are shown onFIG. 4 and 5, illustrating a tool 26 guided in its operational position.In this case the tool is guided for axial motion through guidingelements 9, 11. Element 11 is stationary and is, together with guidingand gripping element 9 of the upper tool exchange unit, forming acircular cylindrical guiding surface for the cylindrical peripheralsurface of the tool. The tool has a guiding key 27 extending into theaxial groove 25, and can be locked to element 9 or released therefrom byaxial displacement of slide 16, as described above. The operation of theupper tool exchange unit generally corresponds to the operation of thelower unit. The tool is seized in its starting position A andtransferred to operational position by means of element 9. Element 9 isaligned with stationary element 11 by means of guiding pin 12 andguiding key 13 which engage stationary hardened inserts l4 and 15,respectively, in element 11. As the tool 26 in this case has to performan axial motion in its operational position, the slide 16 is reset forbringing its recess 19 in front of guiding key 27 of the tool, thusenabling the tool to move in axial direction. By cooperation of thefixed element 11 and element 9 an accurate radial guiding of the tool 26during its axial motion is obtained.

Stationary operating units 20, 21 are mounted on each side of element 9in its starting position A and in its operational position B for settingslide 16 in a first locking position and a second release position,respectively. Said units preferably comprise pressure fluid operatedcylinder jacks.

The operation of the device is described below with reference to theabove mentioned figures and to FIG. 6. The movable gripping and guidingelements of each unit are denominated 9' and 9" respectively, in orderto better clarify the representation of the invention in FIG. 6.

l. Fetching operation.

Tool magazine 28 contains pairs of pre-adjusted tools for carrying outdesired work operations. The tools are mounted in the magazine withtheir guiding keys extending towards the respective grooves 25 inelements 9, in alignment therewith. For receiving a pair of toolsaccording to a predetermined program the magazine comprising a number ofsuperimposed pairs of turret discs is rotated and vertically displacedfor positioning the desired tools in starting position A. Slides 5 ofslide systems 2 are extended to approach the tool magazine for bringingthe supporting surfaces of gripping and guiding elements 9" intoengagement with corresponding surfaces of the tools. The guiding keys 27are introduced into grooves 25 in elements 9". The slides 16 are set intheir free position with recess 19 in=front of groove 25. Pressure fluidis supplied to operating units positioned adjacent the upper and thelower tool in the magazine for displacing slides 16in order to engageswallow-tail section portions 18 with corresponding recesses in the toolkeys. Slides 5 are returned to their starting position by cylinder jacks7, thereby taking the tools out of the magazine.

At the same time or earlier the opposite slides4 are returned tocorresponding retracted position.

2. Exchange operation.

The upper and the lower tool exchange units are simultaneously rotated180 about the axis of fulcrum 3 by means of cylinder jacks 8. Slides 5together with gripping and guiding elements 9" and the tools receivedtherein are extended by means of cylinder jacks 7 towards operatingposition B. Elements 9" are guided into and attached to the respectivestationary guiding elements 10, 11. The upper tool is connected with themechanism of the machine and slide 16 is reset in free position byoperating unit 21. Being radially guided, the upper tool can thereafterperform its reciprocating motion. The lower tool is fixedly securedradially and axially by elements 9" and 10.

3. Work operation.

4. Returning operation.

After finishing the above work operation the slide 16 is reset in itslocking position by means of operating unit 20 adjacent operatingposition B and the tool is locked to element 9". The lower tool stillbeing locked to its gripping and guiding element 9" and thecorrespondingly locked upper tool are simultaneously retracted togetherwith slides 5 by means of cylinder jacks 7. The tools to be used in thefollowing work operation are supported in retracted position on theirgripping and guiding elements 9'. Both tool excha nge units are turned180 about the axis of fulcrum 3. Elements 9'' return their tools to thepre-set receiving seats in the tool magazine. The tools are releasedfrom elements 9" by means of operating units 21 at the magazine andelements 9" are returned in retracted position in the tool exchangeunits. Gripping and guiding elements 9 will thereafter bring their toolsin operational positions, the upper tool being connected with thedriving mechanism of the machine and released for axial motion. Thelower tool will be maintained in fixed position. When these tools areperforming their work, the tool magazine will bring the following pairof tools into starting position.

The above working cycle is repeated until the predetermined program hasbeen completed. Thereafter the tools are again received in theirpredetermined positions in the tool magazine.

In the foregoing example the invention has been described as includingtwo cooperating tools whichare simultaneously performing a parallelworking and exchange cycle. This is the normal case for nibbling andpunching machines. It is, however, also possible to apply the inventionfor exchange of one tool only for cooperation with a second stationarytool in the machine. In such case it is sufficient to use one toolexchange unit only.

I claim:

1. In combination with a machine tool having a tool guiding surface forguiding in operation in a movable tool when same is in a workingposition wherein same may be moved by said machine tool, an apparatusfor transferring said tool between a non-working position and saidworking position comprising: movable gripping means for releasablygripping said tool for moving same between said working position andsaid nonworking position and having means coacting with said toolguiding surface for alternatively holding said tool in said workingposition and guiding same during movement by said machine tool; andtranspecting means for moving said gripping means and to effect transferof said tool between said non-working position and said workingposition.

2. Apparatus according to claim 1 wherein said machine tool includesanother guiding surface aligned with said first mentioned guidingsurface; and including another movable gripping means for releasablygripping a stationary tool for moving same between a nonworking positionand a working position and coacting with said another guiding surfacefor holding said stationary tool in said working position when samecooperates with said movable tool for working on a workpiece duringoperation of the machine tool, and another transporting means for movingsaid another gripping means and to effect transfer of said tool betweensaid non-working position and said working position.

3. An apparatus according to claim 2 including means on said movabletool defining a guiding key;'and wherein said gripping means has meanstherein defining a guiding keyway coacting in operation with saidguiding key to guide said movable tool as same moves and for positioningsaid movable tool in said gripping means.

4. An apparatus according to claim 3 wherein said gripping meansincludes locking means for locking said movable tool therein comprisingmeans in said guiding key defining a locking groove, means defining abore in said gripping means, a slide member slidable in said borebetween a locked position and an unlocked position and having anengaging portion engageable with said locking groove for locking saidmovable tool in said gripping means when said slide member is in saidlocked position, and slide moving means for selectively moving saidslide member between said locked position and said unlocked positionwhen said gripping means is in said working position or said non-workingposition.

5. An apparatus according to claim 2 including means on said stationarytool defining a key; and wherein said another gripping means has meanstherein defining a keyway engageable with said key for positioning saidstationary tool in said another gripping means.

6. An apparatus according to claim 5 wherein said another gripping meansincludes locking means for slide member is in said locked position, andslide moving means for selectively moving said slide member between saidlocked position and said unlocked position when said gripping means andsaid stationary tool are in said non-working position.

1. In combination with a machine tool having a tool guiding surface forguiding in operation a movable tool when same is in a working positionwherein same may be moved by said machine tool, an apparatus fortransferring said tool between a non-working position and said workingposition comprising: movable gripping means for releasably gripping saidtool for moving same between said working position and said non-workingposition and having means coacting with said tool guiding surface foralternatively holding said tool in said working position and guidingsame during movement by said machine tool; and transpecting means formoving said gripping means and to effect transfer of said tool betweensaid non-working position and said working position.
 2. Apparatusaccording to claim 1 wherein said machine tool includes another guidingsurface aligned with said first mentioned guiding surface; and includinganother movable gripping means for releasably gripping a stationary toolfor moving same between a non-working position and a working positionand coacting with said another guiding surface for holding saidstationary tool in said working position when same cooperates with saidmovable tool for working on a workpiece during operation of the machinetool, and another transporting means for moving said another grippingmeans and to effect transfer of said tool between said non-workingposition and said working position.
 3. An apparatus according to claim 2including means on said movable tool defining a guiding key; and whereinsaid gripping means has Means therein defining a guiding keyway coactingin operation with said guiding key to guide said movable tool as samemoves and for positioning said movable tool in said gripping means. 4.An apparatus according to claim 3 wherein said gripping means includeslocking means for locking said movable tool therein comprising means insaid guiding key defining a locking groove, means defining a bore insaid gripping means, a slide member slidable in said bore between alocked position and an unlocked position and having an engaging portionengageable with said locking groove for locking said movable tool insaid gripping means when said slide member is in said locked position,and slide moving means for selectively moving said slide member betweensaid locked position and said unlocked position when said gripping meansis in said working position or said non-working position.
 5. Anapparatus according to claim 2 including means on said stationary tooldefining a key; and wherein said another gripping means has meanstherein defining a keyway engageable with said key for positioning saidstationary tool in said another gripping means.
 6. An apparatusaccording to claim 5 wherein said another gripping means includeslocking means for locking said stationary tool therein comprising meansin said key defining a locking groove, means defining a bore in saidanother gripping means, a slide member slidable in said bore between alocked position and an unlocked position and having an engaging portionengageable with said locking groove for locking said stationary tool insaid another gripping means when said slide member is in said lockedposition, and slide moving means for selectively moving said slidemember between said locked position and said unlocked position when saidgripping means and said stationary tool are in said non-workingposition.